The present invention relates to a data recording system for recording in a CD-ROM or similar recording medium a data file containing data such as compressed audio and video data and an index file containing index data for searching the individual data of the data file. More particularly, the present invention is concerned with the formats of the data and index files. Equipment of the type using optical disks has been developed in a variety of forms. Among the optical disks, digital audio disks in the form of compact disks (CD) are predominant in the audio disk market over traditional LP disks or similar grooved disks due to the non-contact playback and faithful sound reproduction capabilities. Today, extended applications of such CDs to personal computers and other various data processing equipment as mass storages are attempted to take advantage of the extremely great storage capacity and the ease of handling and replacement. For example, CR-ROMs, CD-Is (Interactive) and CD-ROM/XAs (Extended Architecture) are the recent achievements. Such a latest type of CD is capable of recording not only text, graphics and other still pictures but also moving pictures, sound and various kinds of codes in combination, and reproducing the individual data in an interactive fashion.
It has been customary to compress audio data and video data including still and moving pictures when it is desired to record them together in the above-described type of recording medium. The compression is successful in promoting rapid read-out of the individual data at the time of playback. Index data associated with the individual data are recorded in the medium together with the video data, so that the compressed audio and video data may be searched to read out desired data. A prerequisite is, therefore, that a data file containing the auido and video data and an index file containing the index data each be provided with a particular format that allows the data to be readily prepared, edited, recorded, reproduced, and searched at the time of reproduction. Formats and data recording systems which meet such a requirement have not been been reported yet. The problem with CD-Is and CD-ROM/XAs adopting a sector interleave system which uses the subcode of CDs is that they cannot record audio and video data efficiently and cannot easily synchronize the two different kinds of data in the event of playback.